What to Do When the Engine Fault Light Comes On in a New Car?
3 Answers
If the engine fault light comes on, you can follow these steps to address the issue: First, check whether the engine is running normally. Look for signs such as shaking, black smoke emission, or difficulty starting. If any of these issues are present, avoid restarting the engine. Note: If the light is red, do not restart the engine under any circumstances. If the engine is running normally and the car can be driven, proceed to a service station as soon as possible to diagnose the problem. The service station can easily read the fault code using a portable diagnostic tool, allowing for targeted repairs based on the fault information. If the engine is running normally, the owner can also try gently reconnecting all wiring harness connectors, as a loose connection might be the cause. Alternatively, repeatedly turning the key to the ON position might reset the light. Generally, the engine fault light may come on due to the following seven reasons: Sensor malfunction: This includes sensors such as the coolant temperature sensor, crankshaft position sensor, air flow sensor, intake air temperature sensor, and oxygen sensor. If these sensors are damaged, poorly connected, or their signals are interrupted, the car's ECU cannot accurately obtain engine data, triggering the fault light. Fuel or oil quality issues: If the recommended fuel or engine oil is not used, it may cause engine wear, leading to the fault light illuminating. Poor combustion of the air-fuel mixture: This can result in engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the fault light will turn on as a warning. Issues such as faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can cause poor combustion. Turbocharger problems: Issues with the intake boost pipes or turbocharger can also trigger the engine fault light. The most common issue is a damaged turbocharger, accompanied by symptoms such as oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: If the car's intake system is compromised, it may lead to clogged engine pipes, which can, in severe cases, trigger the fault light. A dirty or uncleaned air filter can cause intake issues. Exhaust problems: Exhaust system faults can also cause the engine fault light to come on. Common causes include faulty rear oxygen sensors, catalytic converters, exhaust camshafts, or bearings. The catalytic converter is the most frequent culprit. Using leaded gasoline, lead- or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system issues can all lead to catalytic converter failure. Anti-theft system malfunction: If the car's electronic anti-theft system fails or the anti-theft controller does not match the engine's electronic controller, the anti-theft system may prevent the engine from operating normally, triggering the fault light.
Don't panic when the engine warning light suddenly comes on! I once experienced this while driving my brand-new car on the highway. Immediately ease off the accelerator, gradually pull over to the emergency lane, and turn on the hazard lights. For new cars, there are generally three possibilities: poor fuel quality causing incomplete combustion, a loose fuel tank cap triggering the sensor, or a sensor malfunction giving a false alarm. In my case, it was due to substandard 92-octane fuel from the gas station, and the light turned off after restarting. If the light comes back on after restarting, don't hesitate—call for a tow truck immediately. Don’t listen to anyone suggesting you drive to a repair shop; new cars have warranties, and the dealership should handle the inspection. Remember to keep the windows open while driving—if there’s a real issue, you might smell burning.
Last week, while accompanying a friend to pick up his new car, we encountered the engine warning light turning yellow, and he was sweating with anxiety. I advised him not to turn off the engine immediately, shift to P mode, engage the handbrake, and then I crouched in front of the car to listen to the engine sound. The probability of mechanical failure in a new car is less than 5%, and it's mostly the electronic system acting up. Common issues include the oxygen sensor being clogged by moisture or the new car's catalytic converter not being properly broken in. Remember to wait for 5 minutes after turning off the engine before restarting; sometimes, the car's computer just needs a reboot. If the light stubbornly remains on, take a video of the dashboard with your phone and directly call the dealership's rescue hotline. Don't randomly pull out fuses yourself; tampering with a new car might void the warranty!
